On Fri, 17 Feb 2023 09:50:16 GMT, Sergey Tsypanov <stsypa...@openjdk.org> wrote:
> 1) When `DateTimeFormatter` is reused we don't need to copy > `availableZoneIds` and allocate `nonRegionIds` as PrefixTree can be taken > from cache. In the related benchmark allocation of `HashSet` takes ~93% of > all time, so avoiding it should bring some improvement for cases when we > reuse `DateTimeFormatter` to parse a string into `ZoneDateTime` >  > > 2) `DateTimeFormatter` is mostly used with one locale, so `cachedTree` and > `cachedTreeCI` can have predefined size. > > > @State(Scope.Thread) > @BenchmarkMode(Mode.AverageTime) > @OutputTimeUnit(TimeUnit.NANOSECONDS) > public class DateTimeFormatterBenchmark { > > private static final DateTimeFormatter df = new > DateTimeFormatterBuilder().appendPattern("yyyy:MM:dd:HH:mm:v").toFormatter(); > private static final String TEXT = "2015:03:10:12:13:ECT"; > > @Setup > public void setUp() { > ZonedDateTime.parse(TEXT, df); > } > > @Benchmark > public ZonedDateTime parse() { > return ZonedDateTime.parse(TEXT, df); > } > } Benchmarking make test TEST="micro:time.format.ZonedDateTimeFormatterBenchmark" MICRO="OPTIONS=-prof gc" master Benchmark Mode Cnt Score Error Units ZonedDateTimeFormatterBenchmark.parse avgt 20 13545.737 ± 451.164 ns/op ZonedDateTimeFormatterBenchmark.parse:·gc.alloc.rate avgt 20 1713.579 ± 56.517 MB/sec ZonedDateTimeFormatterBenchmark.parse:·gc.alloc.rate.norm avgt 20 24320.006 ± 0.001 B/op ZonedDateTimeFormatterBenchmark.parse:·gc.count avgt 20 110.000 counts ZonedDateTimeFormatterBenchmark.parse:·gc.time avgt 20 514.000 ms patch Benchmark Mode Cnt Score Error Units ZonedDateTimeFormatterBenchmark.parse avgt 20 1276.063 ± 52.543 ns/op ZonedDateTimeFormatterBenchmark.parse:·gc.alloc.rate avgt 20 622.223 ± 26.456 MB/sec ZonedDateTimeFormatterBenchmark.parse:·gc.alloc.rate.norm avgt 20 832.001 ± 0.001 B/op ZonedDateTimeFormatterBenchmark.parse:·gc.count avgt 20 58.000 counts ZonedDateTimeFormatterBenchmark.parse:·gc.time avgt 20 475.000 ms ------------- PR Comment: https://git.openjdk.org/jdk/pull/12612#issuecomment-1483893997
